It is known to process the surface of a component such as an aerofoil (e.g. a blade or vane) for a gas turbine engine by polishing or linishing to remove small amounts of material in order to obtain the required surface profile and/or finish. This is typically carried out using a belt having an abrasive surface that is rotated on a wheel about an axis that extends parallel to the component surface whilst the abrasive surface is moved over and against the component surface along a continuous toolpath at a constant pressure. The granular nature of the abrasive surface removes surface irregularities on the component surface as the abrasive surface moves over and against the component surface.
Prolonged use of the abrasive belt gradually reduces the granular nature of the abrasive surface such that the effectiveness of the abrasive surface is gradually reduced. This means that areas of the component surface that are processed during the early stages of the continuous toolpath of the abrasive surface are much more effectively processed (i.e. the desired level of material removal is achieved) than the areas of the component surface that are processed during the later stages of the continuous toolpath of the abrasive surface (where a lower level of material removal is achieved). This can lead to an inconsistent surface profile/finish across the component surface.
Replacing the abrasive surface as soon as its effectiveness is sub-optimal can significantly increase the processing cost.
There is the need for a processing method that allows accurate control of the amount of material removal across an entire component surface even when the abrasive nature of the abrasive surface is sub-optimal.